Patent Literature 1 is an example of a conventional slide rail device. The slide rail device is equipped with a pair of left and right lower rails extending in a forward/rearward direction which are fixed to a vehicle interior floor, and a pair of left and right upper rails which support the seating portion of a seat and are slideably supported by the left and right lower rails.
A pair of left and right stopper portions are respectively provided, by being cut and raised, near the front end and near the rear end of each upper rail. Whereas, a pair of left and right restricting lugs are provided on each lower rail by being cut and raised. Upon assembling the upper rail onto the lower rail, the restricting lugs are positioned in between the stopper portions.
Therefore, the forward sliding-extremity position of the upper rails (seat) relative to the lower rails is determined by the position of contact of the left and right restricting lugs with the front left and right stoppers, respectively, and the rearward sliding-extremity position thereof is determined by the position of contact of the left and right restricting lugs with the rear left and right stoppers, respectively.